Field
The present disclosure relates generally to transmission of data by active implantable medical devices, and more particularly, to apparatuses and methods for optimizing the transmission of data from active implantable medical devices.
Background
Modern active implantable medical devices, such as neurostimulators, pacemakers, and ICDs, are capable of not only monitoring patient condition and delivering therapy, but are capable of storing detailed data and diagnostics relating to a patient's condition for later retrieval. Analysis of this data can improve patient care dramatically, and allow fine-tuning the performance of the implantable devices by programming them with new operational parameters. Interrogation of an implantable medical device allows data stored in the device to be retrieved by an external device. After analysis, reprogramming the device allows its performance to be optimized based on the interrogated data.
Often it is desirable to store large quantities of data in the implantable device until such time as the data can be transmitted from the implantable device to external equipment such as a physician programmer or a home data monitor. Once the physiologic data has been retrieved by the external equipment it is often incorporated into data repository and made available for display and analysis. The resources available in an implantable device are often very limited. For example, the memory resources aboard an implantable device are limited by the small physical size constraints imposed on the design. Only physically small and low power memory media are practical for this use. Typically, this limits the design to relatively small storage capacity CMOS static RAM or similar devices.
The power source for implantable devices is often a small primary cell (non-rechargeable battery). The usable service life of an implantable device is typically determined by how quickly the battery is depleted. When the battery is depleted the usable service life is over. Minimizing the duration of high power activities such as telemetry reduces the rate of battery depletion and so increases useful service life.
Implantable medical device systems often include a home data monitor. This provides the opportunity to upload physiologic data conveniently and often. This reduces the demand for memory space onboard the implantable device by affording opportunities to retrieve the contents of this memory often. However, the home data monitor also increases the demand for transporting large quantities of data over telemetry to external equipment. This increased telemetry activity increases the rate of battery depletion thereby reducing the useable service life for the implantable device.
It would be desirable to provide mechanisms that optimize the retrieval of patient data in a manner that reduces implantable medical device energy consumption and conserves memory space. The concepts disclosed below address these needs and others.